You know how, in movies, sometimes in the big car-chase scene there's a sequence where the hero cranes his neck, looks out the rear windshield, hits the gas and miraculously weaves his way through oncoming traffic until he slams the brakes, turns the wheel and executes a perfect reverse-K turn? Or at least something like that?

The reason it seems so impressive -- or just plain unbelievable, if you prefer -- is that we all know just how hard it is to drive backwards at anything more than a snail's pace. Professional drivers aside, people tend to have a seemingly disproportionately difficult time going in reverse. But as it turns out, there's a good reason for that. It has to do with levels of separation and, somehow, can be partially explained by watching a man perilously balance an axe on his palm.

Henry Reich, the smart guy behind @MinutePhysics, put together the above video, which helpfully uses pictures and small words to walk the viewer through the driving-backwards problem slowly and sensibly. After watching it, you may actually understand what's going on. That may not make it any easier the next time you have to back out of the garage all the way down the long, narrow driveway and into the street, but at least you'll know why can't do it faster than 4 mph.